Campbell Scientific has introduced a new operating system, OS13, for the CS120A visibility sensor and CS125 present weather sensor. It is fully backwards compatible and is easily installed on all CS120A and CS125 sensors (but not older CS120 sensors). OS13 is available free of charge and can be downloaded here or supplied by email on request.
Upgrade to OS 13 is recommended.
Changes to both CS120A and CS125
To optimise user calibrations, OS13 temporarily disables hood heaters during calibration and resumes normal hood functionality once the calibration is complete.
Hood heaters now operate down to the fault alarm levels of -56°C, but will turn off at low temperatures if a thermistor fault is detected.
OS13 better flags DC saturation, which under very bright conditions might occasionally produce a dirty lens alarm.
OS13 has corrected the potential for level 1 dirty window alarms to occur during heavy fog and rain where visibility drops below 10m.
Changes to CS125 only
OS13 contains improved filtering to reduce the occurrence of short duration precipitation reports caused by transient insect activity. The sensor still retains its sensitivity to the detection of precipitation.
Automatic optimisation to differing background light levels reduce the occurrence of erroneous particles reported in bright light.
OS13 includes a software switch to turn off BCFG from the CS125 message output. If triggered by broken fog, the BCFG message could affect AWOS systems. This does not affect the CS120A.